Cutting Back Penstemons
I have a couple of very large Penstemons in my garden, which were lovely for a couple of years, but got too large so I cut them back. They are still growing well but I had virtually no flowers last summer. Was this because I cut them back at the wrong time, in the wrong way or was it to do with the awful weather last year. I need to cut them back again but would like to get it right this time. Can anyone help?